test: assert/ignore some warn_unused_result's

Signed-off-by: Ran Benita <ran234@gmail.com>

bench/bench.c

@@ -33,6 +33,7 @@
 #include <sys/time.h>
 #endif
 
+#include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -139,10 +140,12 @@ bench_timer_get_elapsed_time_str(struct bench_timer *self)
 {
     struct bench_time elapsed;
     char *buf;
+    int ret;
 
     bench_timer_get_elapsed_time(self, &elapsed);
     normalize_bench_time(&elapsed);
-    asprintf(&buf, "%ld.%06ld", elapsed.seconds, elapsed.milliseconds);
+    ret = asprintf(&buf, "%ld.%06ld", elapsed.seconds, elapsed.milliseconds);
+    assert(ret >= 0);
 
     return buf;
 }

test/interactive-evdev.c

@@ -483,14 +483,14 @@ main(int argc, char *argv[])
     sigaction(SIGTERM, &act, NULL);
 
     /* Instead of fiddling with termios.. */
-    system("stty -echo");
+    (void) system("stty -echo");
 
     ret = loop(kbds);
     if (ret)
         goto err_stty;
 
 err_stty:
-    system("stty echo");
+    (void) system("stty echo");
     free_keyboards(kbds);
 err_compose:
     xkb_compose_table_unref(compose_table);

test/interactive-x11.c

@@ -372,9 +372,9 @@ main(int argc, char *argv[])
         goto err_core_kbd;
     }
 
-    system("stty -echo");
+    (void) system("stty -echo");
     ret = loop(conn, &core_kbd);
-    system("stty echo");
+    (void) system("stty echo");
 
 err_core_kbd:
     deinit_kbd(&core_kbd);